 package com.justsafe.domain.http;


 import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.RSAPublicKeySpec;
import java.security.spec.X509EncodedKeySpec;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;


 /**
  * @author Mr.Zheng
  * @date 2014年8月22日 下午1:44:23
  */
 public final class RSAUtils {
     /*android客户端用这个*/
     private static String RSA = "RSA/ECB/PKCS1Padding";



     /**
      * 随机生成RSA密钥对(默认密钥长度为1024)
      *
      * @return
      */
     public static KeyPair generateRSAKeyPair()
     {
         return generateRSAKeyPair(1024);
     }

     /**
      * 随机生成RSA密钥对
      *
      * @param keyLength
      *            密钥长度，范围：512～2048<br>
      *            一般1024
      * @return
      */
     public static KeyPair generateRSAKeyPair(int keyLength)
     {
         try
         {
             KeyPairGenerator kpg = KeyPairGenerator.getInstance(RSA);
             kpg.initialize(keyLength);
             return kpg.genKeyPair();
         } catch (NoSuchAlgorithmException e)
         {
             e.printStackTrace();
             return null;
         }
     }
     /**
      * 使用公钥对明文进行加密
      * @param publicKey      公钥
      * @param plainText      明文
      * @return
      */
     public static String encrypt(String publicKey, String plainText){
         try {
             Cipher cipher = Cipher.getInstance(RSA);
             cipher.init(Cipher.ENCRYPT_MODE,getPublicKey(publicKey));
             byte[] bytes = plainText.getBytes();
             ByteArrayInputStream read = new ByteArrayInputStream(bytes);
             ByteArrayOutputStream write = new ByteArrayOutputStream();
             byte [] buf=new byte[117];
             int len=0;
             while ( (len=read.read(buf))!=-1 ){
                 byte [] buf1=null;
                 if(buf.length==len){
                     buf1=buf;
                 }else{
                     buf1=new byte[len];
                     for (int i = 0; i < len; i++) {
                         buf1[i]=buf[i];
                     }
                 }
                 byte[] bytes1 = cipher.doFinal(buf1);
                 write.write(bytes1);
             }
             return Base64.encode(write.toByteArray());
         } catch (InvalidKeyException e) {
             e.printStackTrace();
         } catch (IllegalBlockSizeException e) {
             e.printStackTrace();
         } catch (BadPaddingException e) {
             e.printStackTrace();
         } catch (Exception e) {
             e.printStackTrace();
         }
         return null;
     }

     /**
      * 使用私钥对密文进行解密
      * @param privateKey       私钥
      * @param enStr            密文
      * @return
      */
     public static String decrypt(String privateKey, String enStr){
         try {
             Cipher cipher = Cipher.getInstance(RSA);
             cipher.init(Cipher.DECRYPT_MODE, getPrivateKey(privateKey));

             byte[] bytes = Base64.decode(enStr);
             ByteArrayInputStream read = new ByteArrayInputStream(bytes);
             ByteArrayOutputStream write = new ByteArrayOutputStream();
             byte [] buf=new byte[1024];
             int len=0;
             while ( (len=read.read(buf))!=-1 ){
                 byte [] buf1=null;
                 if(buf.length==len){
                     buf1=buf;
                 }else{
                     buf1=new byte[len];
                     for (int i = 0; i < len; i++) {
                         buf1[i]=buf[i];
                     }
                 }
                 byte[] bytes1 = cipher.doFinal(buf1);
                 write.write(bytes1);
             }
             return new String(write.toByteArray());
         } catch (InvalidKeyException e) {
             e.printStackTrace();
         } catch (IllegalBlockSizeException e) {
             e.printStackTrace();
         } catch (BadPaddingException e) {
             e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
         } catch (Exception e) {
             e.printStackTrace();
         }
         return null;
     }


     /**
      * 得到公钥
      *
      * @param key
      *            密钥字符串（经过base64编码）
      * @throws Exception
      */
     public static PublicKey getPublicKey(String key) throws Exception {
         byte[] keyBytes;
 //        keyBytes = (new BASE64Decoder()).decodeBuffer(key);
         keyBytes= Base64.decode(key);
         X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
         KeyFactory keyFactory = KeyFactory.getInstance("RSA");
         PublicKey publicKey = keyFactory.generatePublic(keySpec);
         return publicKey;
     }

     /**
      * 得到私钥
      *
      * @param key
      *            密钥字符串（经过base64编码）
      * @throws Exception
      */
     public static PrivateKey getPrivateKey(String key) throws Exception {
         byte[] keyBytes;
 //        keyBytes = (new BASE64Decoder()).decodeBuffer(key);
         keyBytes= Base64.decode(key);
         PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
         KeyFactory keyFactory = KeyFactory.getInstance("RSA");
         PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
         return privateKey;
     }


     //=============================================================================================
     /**
      * 用公钥加密 <br>
      * 每次加密的字节数，不能超过密钥的长度值减去11
      *
      * @param
      *
      * @param
      *
      * @return 加密后的byte型数据
      */
     public static byte[] encryptData(byte[] data, PublicKey publicKey)
     {
         try
         {
             Cipher cipher = Cipher.getInstance(RSA);
             // 编码前设定编码方式及密钥
             cipher.init(Cipher.ENCRYPT_MODE, publicKey);
             // 传入编码数据并返回编码结果
             return cipher.doFinal(data);
         } catch (Exception e)
         {
             e.printStackTrace();
             return null;
         }
     }

     /**
      * 用私钥解密
      *
      * @param encryptedData
      *            经过encryptedData()加密返回的byte数据
      * @param privateKey
      *            私钥
      * @return
      */
     public static byte[] decryptData(byte[] encryptedData, PrivateKey privateKey)
     {
         try
         {
             Cipher cipher = Cipher.getInstance(RSA);
             cipher.init(Cipher.DECRYPT_MODE, privateKey);
             return cipher.doFinal(encryptedData);
         } catch (Exception e)
         {
             return null;
         }
     }

     /**
      * 通过公钥byte[](publicKey.getEncoded())将公钥还原，适用于RSA算法
      *
      * @param keyBytes
      * @return
      * @throws NoSuchAlgorithmException
      * @throws InvalidKeySpecException
      */
     public static PublicKey getPublicKey(byte[] keyBytes) throws NoSuchAlgorithmException,
             InvalidKeySpecException
     {
         X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
         KeyFactory keyFactory = KeyFactory.getInstance(RSA);
         PublicKey publicKey = keyFactory.generatePublic(keySpec);
         return publicKey;
     }

     /**
      * 通过私钥byte[]将公钥还原，适用于RSA算法
      *
      * @param keyBytes
      * @return
      * @throws NoSuchAlgorithmException
      * @throws InvalidKeySpecException
      */
     public static PrivateKey getPrivateKey(byte[] keyBytes) throws NoSuchAlgorithmException,
             InvalidKeySpecException
     {
         PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
         KeyFactory keyFactory = KeyFactory.getInstance(RSA);
         PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
         return privateKey;
     }

     /**
      * 使用N、e值还原公钥
      *
      * @param modulus
      * @param publicExponent
      * @return
      * @throws NoSuchAlgorithmException
      * @throws InvalidKeySpecException
      */
     public static PublicKey getPublicKey(String modulus, String publicExponent)
             throws NoSuchAlgorithmException, InvalidKeySpecException
     {
         BigInteger bigIntModulus = new BigInteger(modulus);
         BigInteger bigIntPrivateExponent = new BigInteger(publicExponent);
         RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent);
         KeyFactory keyFactory = KeyFactory.getInstance(RSA);
         PublicKey publicKey = keyFactory.generatePublic(keySpec);
         return publicKey;
     }

     /**
      * 使用N、d值还原私钥
      *
      * @param modulus
      * @param privateExponent
      * @return
      * @throws NoSuchAlgorithmException
      * @throws InvalidKeySpecException
      */
     public static PrivateKey getPrivateKey(String modulus, String privateExponent)
             throws NoSuchAlgorithmException, InvalidKeySpecException
     {
         BigInteger bigIntModulus = new BigInteger(modulus);
         BigInteger bigIntPrivateExponent = new BigInteger(privateExponent);
         RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent);
         KeyFactory keyFactory = KeyFactory.getInstance(RSA);
         PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
         return privateKey;
     }

     /**
      * 从字符串中加载公钥
      *
      * @param publicKeyStr
      *            公钥数据字符串
      * @throws Exception
      *             加载公钥时产生的异常
      */
     public static PublicKey loadPublicKey(String publicKeyStr) throws Exception
     {
         try
         {
             byte[] buffer = Base64Utils.decode(publicKeyStr);
             KeyFactory keyFactory = KeyFactory.getInstance(RSA);
             X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);
             return (RSAPublicKey) keyFactory.generatePublic(keySpec);
         } catch (NoSuchAlgorithmException e)
         {
             throw new Exception("无此算法");
         } catch (InvalidKeySpecException e)
         {
             throw new Exception("公钥非法");
         } catch (NullPointerException e)
         {
             throw new Exception("公钥数据为空");
         }
     }

     /**
      * 从字符串中加载私钥<br>
      * 加载时使用的是PKCS8EncodedKeySpec（PKCS#8编码的Key指令）。
      *
      * @param privateKeyStr
      * @return
      * @throws Exception
      */
     public static PrivateKey loadPrivateKey(String privateKeyStr) throws Exception
     {
         try
         {
             byte[] buffer = Base64Utils.decode(privateKeyStr);
             // X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);
             PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);
             KeyFactory keyFactory = KeyFactory.getInstance(RSA);
             return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
         } catch (NoSuchAlgorithmException e)
         {
             throw new Exception("无此算法");
         } catch (InvalidKeySpecException e)
         {
             throw new Exception("私钥非法");
         } catch (NullPointerException e)
         {
             throw new Exception("私钥数据为空");
         }
     }

     /**
      * 从文件中输入流中加载公钥
      *
      * @param in
      *            公钥输入流
      * @throws Exception
      *             加载公钥时产生的异常
      */
     public static PublicKey loadPublicKey(InputStream in) throws Exception
     {
         try
         {
             return loadPublicKey(readKey(in));
         } catch (IOException e)
         {
             throw new Exception("公钥数据流读取错误");
         } catch (NullPointerException e)
         {
             throw new Exception("公钥输入流为空");
         }
     }

     /**
      * 从文件中加载私钥
      *
      * @param
      *
      * @return 是否成功
      * @throws Exception
      */
     public static PrivateKey loadPrivateKey(InputStream in) throws Exception
     {
         try
         {
             return loadPrivateKey(readKey(in));
         } catch (IOException e)
         {
             throw new Exception("私钥数据读取错误");
         } catch (NullPointerException e)
         {
             throw new Exception("私钥输入流为空");
         }
     }

     /**
      * 读取密钥信息
      *
      * @param in
      * @return
      * @throws IOException
      */
     private static String readKey(InputStream in) throws IOException
     {
         BufferedReader br = new BufferedReader(new InputStreamReader(in));
         String readLine = null;
         StringBuilder sb = new StringBuilder();
         while ((readLine = br.readLine()) != null)
         {
             if (readLine.charAt(0) == '-')
             {
                 continue;
             } else
             {
                 sb.append(readLine);
                 sb.append('\r');
             }
         }

         return sb.toString();
     }

     /**
      * 打印公钥信息
      *
      * @param publicKey
      */
     public static void printPublicKeyInfo(PublicKey publicKey)
     {
         RSAPublicKey rsaPublicKey = (RSAPublicKey) publicKey;
         System.out.println("----------RSAPublicKey----------");
         System.out.println("Modulus.length=" + rsaPublicKey.getModulus().bitLength());
         System.out.println("Modulus=" + rsaPublicKey.getModulus().toString());
         System.out.println("PublicExponent.length=" + rsaPublicKey.getPublicExponent().bitLength());
         System.out.println("PublicExponent=" + rsaPublicKey.getPublicExponent().toString());
     }

     public static void printPrivateKeyInfo(PrivateKey privateKey)
     {
         RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) privateKey;
         System.out.println("----------RSAPrivateKey ----------");
         System.out.println("Modulus.length=" + rsaPrivateKey.getModulus().bitLength());
         System.out.println("Modulus=" + rsaPrivateKey.getModulus().toString());
         System.out.println("PrivateExponent.length=" + rsaPrivateKey.getPrivateExponent().bitLength());
         System.out.println("PrivatecExponent=" + rsaPrivateKey.getPrivateExponent().toString());

     }

 }
